Help needed with Bunny Blanket Buddy

I have completed the head portion of the Lion Brand Bunny Blanket Buddy, but am very confused about how to form the ears. This is the line I do not understand after “Shape Ears”:
P3tog, return st to left needle, cast on 17 st,p3tog,p15-16 sts on right needle,25 sts on left needle.

Do you cast on the 17 stitches on the left needle? (the same needle you just returned the p3tog stitch? Then purl the first 3 together, then what? I am pretty confused. Thanks for any enlightenment you can provide.

I read it as cast on 17 stitches to the left needle. Then purl 3tog and purl 15 stitches (the ones you cast on).

You’ll end up with 16 stitches on the right needle and should have 25 on the left.